To be fair, they did "up" the Touch Bar this year in a number of ways. Just not in the way you're looking for.
On the hardware-side of things, the Touch Bar now supports TrueTone on the new MBPs which is great.
On the software-side, Mojave now allows you to create "Action Bundles" via Automator and put them right into the Touch Bar which allows you to basically put any chain of supported actions as a shortcut there. This is a pretty underrated change as it now allows you to create basically any chain of supported actions you want and trigger them via a single press of the Touch Bar. Don't like the standard selection of buttons you can put in the Touch Bar? Want to trigger more complex and personalized workflows from the TB? Mojave allows you to do that, right from there.
One of the main criticisms of the Touch Bar has always been that Apple doesn't give the user enough freedom of what to do with it, and this is a definite step in the right direction; it enables you to do lots of stuff natively that previously was only possible with tools like BetterTouchTool. (Source:
Platforms State of the Union, about minute 24)
There are also some new things developers can do with the TB in Mojave, though I'm not entirely sure what they are.
About the resolution: I think we'll see a resolution increase for the Touch Bar the same year we get a resolution increase for the MBP display itself, for the simple reason that the Touch Bar has about the same pixel density as the MBP display. Which might still be a couple years away. It doesn't really make much sense to increase the resolution on one of them and keep the resolution of the other one the same. Personally I also don't think the resolution is an issue with the Touch Bar, though then again I'm still waiting for my own one coming in 2 weeks and can only speak from the experience of my visits to the Apple Store.